day04 Django:ORM: 修改表字段 对数据(表记录)的sql语句操作:查询api,模糊查询 图书管理系统   一.Django: ORM模型层   1.修改表字段     在models.py里面直接改,之后执行那两条python语句     python manage.py makemigrations     python manage.py migrate   2.图书管理系统的请求流程     1.查看书籍     2.浏览器:         请求url http://localhost:8000/books/query/    请求方式GET     2.django的urls.py         path('books/query/', views.booksquery, name="booksquery")     3.django的views.py         执行booksquery(request)         查询所有书籍,将查询的queryset数据传入模板,render()渲染出一个booksquery页面     4.templates的booksquery.html文件         编写要渲染的html     5.用户此时可以看到'查看书籍'的页面   3.对数据(表记录)的sql语句操作     3.1.增     3.2.删     3.3.改     3.4.查         3.4.1.查询api     rst = Book.objects.all()                            #查所有                                  #返回的是queryset     rst = Book.objects.filter(price=44, title='go',)    #按条件查                                #返回的是queryset     rst = Book.objects.exclude(price=44,)               #按条件查的取反                          #返回的是queryset     rst = Book.objects.get(title='java',)               #查询的结果只能有一个,否则就报错         #返回的是model对象       rst = Book.objects.all().first()                    #取第一个          #返回的是model对象; 谁来调用: queryset可以调用     rst = Book.objects.all().last()                     #取最后一个        #返回的是model对象; 谁来调用: queryset可以调用     rst = Book.objects.all().order_by('pub_date',)      #排序              #返回的是queryset;  谁来调用: queryset可以调用; 默认升序,降序用.order_by('-pub_date')     rst = Book.objects.all().order_by('nid').reverse()  #翻转              #返回的是queryset;  谁来调用: queryset可以调用order_by('nid').reverse(); 等同于 order_by('-nid')     rst = Book.objects.all().count()                    #计数              #返回的是int;       谁来调用: queryset可以调用     rst = Book.objects.all().exists()                   #判断是否存在记录  #返回的是boolean;   谁来调用: queryset可以调用; 使用的是limit 1,效率高     rst = Book.objects.all().values('title', 'nid')     #按字段取字典      #返回的是queryset;  谁来调用: queryset可以调用     rst = Book.objects.all().values_list('title',)      #按字段取列表      #返回的是queryset;  谁来调用: queryset可以调用     rst = Book.objects.all().values('title').distinct() #去重              #返回的是queryset;  谁来调用: queryset的元组或字典来调用才有意义         3.4.2.模糊查询(双下划线)     rst = Book.objects.filter(price__gt=44)                             #大于     rst = Book.objects.filter(title__startswith='go')                   #以什么开头的     rst = Book.objects.filter(title__istartswith='go')                  #以什么开头的,不区分大小写     rst = Book.objects.filter(title__contains='g')                      #包含     rst = Book.objects.filter(title__icontains='go')                    #包含,不区分大小写     rst = Book.objects.filter(price__in=[100, 200, 300])                #在里面选一个     rst = Book.objects.filter(price__range=[100, 200])                  #在范围里选一个       rst = Book.objects.filter(pub_date__year=2020, pub_date__month=2)   #查日期: 没查到? 需要改配置 USE_TZ = False   4.图书管理系统     4.1.urls.py         增,删,改,查,首页 共5条线 from django.contrib import admin from django.urls import path,re_path from app01 import views urlpatterns = [     path('admin/', admin.site.urls),     path('books/add/', views.booksadd, name="booksadd"),     path('books/query/', views.booksquery, name="booksquery"),     re_path('^$', views.booksquery, name="booksquery"),     re_path('books/delete/(\d+)', views.booksdelete, name="booksdelete"),     re_path('books/edit/(\d+)', views.booksedit, name="booksedit"), ]     4.2.app01/views.py         五条线的视图函数: 具体的逻辑,及展示对应的页面 from django.shortcuts import render, HttpResponse, redirect from app01.models import Book from django.urls import reverse def booksadd(request):     if request.method == "POST":         # 方式一,较繁琐         # title = request.POST.get('title')         # price = request.POST.get('price')         # pub_date = request.POST.get('pub_date')         # publish = request.POST.get('publish')         # book = Book.objects.create(title=title, price=price, pub_date=pub_date, publish=publish)         # 方式二,注意form里的key要和表里的字段名一样         data = request.POST.dict()         del data["csrfmiddlewaretoken"]         book = Book.objects.create(**data)         return redirect(reverse('booksquery'))     else:         return render(request, 'booksadd.html', locals()) def booksquery(request):     book_list = Book.objects.all()     return render(request, 'booksquery.html', locals()) def booksdelete(request,delete_book_id):     Book.objects.filter(nid=delete_book_id).delete()     return redirect(reverse('booksquery')) def booksedit(request, edit_book_id):     if request.method == "POST":         data = request.POST.dict()         del data["csrfmiddlewaretoken"]         book = Book.objects.filter(nid=edit_book_id).update(**data)         return redirect(reverse('booksquery'))     else:         edit_book = Book.objects.filter(nid=edit_book_id)[0]         return render(request, 'booksedit.html', locals())     4.3.templates         4.3.1.booksquery.html 查看书籍的页面 <!DOCTYPE html> <html lang="zh-CN">   <head>     <meta charset="utf-8">     <meta http-equiv="X-UA-Compatible" content="IE=edge">     <meta name="viewport" content="width=device-width, initial-scale=1">     <title>Bootstrap 101 Template</title>     <link href="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css" rel="stylesheet">   </head>   <body>     <h1>查看书籍 ！</h1>     <div class="container">         <div class="row">             <div class="col-md-8 col-md-offset-2">                 <a href="{% url 'booksadd' %}" class="btn btn-primary btn-sm">添加书籍</a>                 <table class="table table-striped table-hover table-bordered">                     <thead>                         <tr>                             <th>编号</th>                             <th>书籍名称</th>                             <th>价格</th>                             <th>出版日期</th>                             <th>出版社</th>                             <th>操作</th>                         </tr>                     </thead>                     <tbody>                         {% for book in book_list %}                             <tr>                                 <td>{{ forloop.counter }}</td>                                 <td>{{ book.title }}</td>                                 <td>{{ book.price }}</td>                                 <td>{{ book.pub_date|date:"Y-m-d" }}</td>                                 <td>{{ book.publish }}</td>                                 <td>                                     <a href="{% url 'booksedit' book.nid %}" class="btn btn-warning btn-sm">编辑</a>                                     <a href="{% url 'booksdelete' book.nid %}" class="btn btn-danger btn-sm">删除</a>                                 </td>                             </tr>                         {% endfor %}                     </tbody>                 </table>             </div>         </div>     </div>     <script src="https://cdn.jsdelivr.net/npm/jquery@1.12.4/dist/jquery.min.js"></script>     <script src="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/js/bootstrap.min.js"></script>   </body> </html>         4.3.2.booksadd.html 增加书籍的页面 <!DOCTYPE html> <html lang="zh-CN">   <head>     <meta charset="utf-8">     <meta http-equiv="X-UA-Compatible" content="IE=edge">     <meta name="viewport" content="width=device-width, initial-scale=1">     <title>Bootstrap 101 Template</title>     <link href="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css" rel="stylesheet">   </head>   <body>     <h1>添加书籍 ！</h1>     <div class="container">         <div class="row">             <div class="col-md-8 col-md-offset-2">                 <form class="form-horizontal" action="{% url 'booksadd' %}" method="post">                     {% csrf_token %}                   <div class="form-group">                     <label for="title" class="col-sm-2 control-label">书籍名称</label>                     <div class="col-sm-10">                       <input type="text" class="form-control" id="title" placeholder="title" name="title">                     </div>                   </div>                   <div class="form-group">                     <label for="price" class="col-sm-2 control-label">价格</label>                     <div class="col-sm-10">                       <input type="text" class="form-control" id="price" placeholder="price" name="price">                     </div>                   </div>                   <div class="form-group">                     <label for="pub_date" class="col-sm-2 control-label">出版日期</label>                     <div class="col-sm-10">                       <input type="date" class="form-control" id="pub_date" placeholder="pub_date" name="pub_date">                     </div>                   </div>                   <div class="form-group">                     <label for="publish" class="col-sm-2 control-label">出版社</label>                     <div class="col-sm-10">                       <input type="text" class="form-control" id="publish" placeholder="publish" name="publish">                     </div>                   </div>                   <div class="form-group">                     <div class="col-sm-offset-2 col-sm-10">                       <button type="submit" class="btn btn-default">提交</button>                     </div>                   </div>                 </form>             </div>         </div>     </div>     <script src="https://cdn.jsdelivr.net/npm/jquery@1.12.4/dist/jquery.min.js"></script>     <script src="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/js/bootstrap.min.js"></script>   </body> </html>         4.3.3.booksedit.html 修改书籍的页面 <!DOCTYPE html> <html lang="zh-CN">   <head>     <meta charset="utf-8">     <meta http-equiv="X-UA-Compatible" content="IE=edge">     <meta name="viewport" content="width=device-width, initial-scale=1">     <title>Bootstrap 101 Template</title>     <link href="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css" rel="stylesheet">   </head>   <body>     <h1>编辑书籍 ！</h1>     <div class="container">         <div class="row">             <div class="col-md-8 col-md-offset-2">                 <form class="form-horizontal" action="{% url 'booksedit' edit_book.nid %}" method="post">                     {% csrf_token %}                   <div class="form-group">                     <label for="title" class="col-sm-2 control-label">书籍名称</label>                     <div class="col-sm-10">                       <input type="text" class="form-control" id="title" placeholder="title" name="title" value="{{ edit_book.title }}">                     </div>                   </div>                   <div class="form-group">                     <label for="price" class="col-sm-2 control-label">价格</label>                     <div class="col-sm-10">                       <input type="text" class="form-control" id="price" placeholder="price" name="price" value="{{ edit_book.price }}">                     </div>                   </div>                   <div class="form-group">                     <label for="pub_date" class="col-sm-2 control-label">出版日期</label>                     <div class="col-sm-10">                       <input type="date" class="form-control" id="pub_date" placeholder="pub_date" name="pub_date" value="{{ edit_book.pub_date|date:'Y-m-d'}}">                     </div>                   </div>                   <div class="form-group">                     <label for="publish" class="col-sm-2 control-label">出版社</label>                     <div class="col-sm-10">                       <input type="text" class="form-control" id="publish" placeholder="publish" name="publish" value="{{ edit_book.publish }}">                     </div>                   </div>                   <div class="form-group">                     <div class="col-sm-offset-2 col-sm-10">                       <button type="submit" class="btn btn-default">提交</button>                     </div>                   </div>                 </form>             </div>         </div>     </div>     <script src="https://cdn.jsdelivr.net/npm/jquery@1.12.4/dist/jquery.min.js"></script>     <script src="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/js/bootstrap.min.js"></script>   </body> </html>